This application is a national stage application of PCT/JP2013/075741, international filing date Sep. 24, 2013, and claims priority to JP 2012-222257, filed in Japan on Oct. 4, 2012, the entire disclosures of which are hereby incorporated by reference in their entirety.
The present invention relates to an electrical junction box in which a cover is assembled to a main body provided with a circuit board, and in particular to an electrical junction box in which a cover is assembled to a main body by being guided by a guiding effect of a guide rib provided on one of the main body and the cover, and a guide groove provided on the other.
Conventionally, electrical junction boxes are used in automobiles and the like in order for electrical components such as fuses, relays, and the like to be arranged efficiently with regard to space, for example. As such an electrical junction box, an electrical junction box as disclosed in, for example, JP 2008-295263A is known that has a structure in which a main body provided with a circuit board such as a printed-circuit board is accommodated in the cover.
Meanwhile, as disclosed in JP 2008-295263A as well, an electrical junction box in which a cover is assembled while accommodating a main body may have a structure in which, in order to externally fit the cover to the main body smoothly, a guide rib is provided protruding from one of a wall section of the main body and the inner surface of the cover, and a guide groove is provided on the other, and the cover is guided to the main body by a guiding effect of the guide rib and the guide groove.
However, in some cases a small gap is created between the open end of the cover and the main body, and water enters the cover via this gap. Furthermore, there is the risk that the water that has entered the cover reaches the circuit board of the main body due to capillary action occurring in the micro-gap between the main body and the cover, possibly causing a short circuit or corrosion of the circuit board. Particularly, when the guide rib and the guide groove are provided, capillary action is highly likely to occur in the micro-gap between the guide rib and the guide groove, and there is the risk that water that has entered the cover from the open end thereof climbs in the guide groove, moves in the micro-gap between the cover and the main body from the guide groove in the direction of the periphery, and thereby reaches the circuit board.